U.S. Pat. No. 2,798,462 (Ludwig et al.); U.S. Pat. No. 3,053,236 (Self et al.); U.S. Pat. No. 3,155,013 (Rumsey); U.S. Pat. No. 3,195,421 (Rumsey et al.); U.S. Pat. No. 3,232,185 (Kummerman); and U.S. Pat. No. 3,583,838 (Stauber), the entirety of each of which are hereby incorporated by reference, describe a variety of control devices, actuators and sealing systems for a range of fluid motors and/or pumps.
Self et al. describe an oscillatory actuator seal system for an actuator assembly of the background art. As seen in FIGS. 1–3 of Self et al., a rotor shaft (element 8) having a pair of diametrically opposed rotor vanes (elements 9 and 10) is provided centrally between a pair of branch rotor shaft vane chambers within a generally rectangularly shaped actuator housing (element 6). The rotor vanes (element 9 and 10) separate the pair of fluid chambers into opposed compartments, i.e., a first vane (element 9) divides a first chamber into a first pair of compartments (elements 11 and 12) and a second vane (element 10) divides a second chamber into a second pair of compartments (elements 13 and 14).
In Self et al., a pressurized control fluid is admitted into the first pair of compartments (elements 11 and 12) through control passages and into the second pair of compartments (elements 13 and 14) through passages (elements 30, 31) extending through the center of the rotor. By varying the pressure conditions in the control passages to create a pressure differential across the first set of vane compartments (elements 11 and 12), the vane (element 9) will be moved toward the region of low pressure. As a result of the movement of the vanes (elements 9 and 10), the rotor shaft (element 8) will oscillate through a controlled and finite angular range that permits the rotor shaft to be connected to a control member, e.g., such as a flight control device. Accordingly, the vaned rotor shaft (elements 9 and 10) serves as a servoactuator for controlling a member through an angular range. Seal members (elements 32 and 33) are provided operatively engaging grooves on opposed sides of the rotor and the surrounding housing (element 6) in order to prevent leakage of control fluid from a high pressure compartment to a low pressure compartment. In addition, the leading edge of each vane (elements 9 and 10) is provided with a seal (elements 36 and 37, respectively) engaging the surrounding housing (element 6) and positioned within a groove formed on the leading edge of the vanes (elements 9 and 10).
The present invention is directed at overcoming shortcomings identified by the present inventors with rotary vane actuators of the aforementioned type, i.e., including actuators having one or more rotor vanes and forming two or more pressurized compartments.